The present invention relates to a plate handling apparatus comprising a new plate inserting device which supplies a new plate to the plate cylinder of a printing press, an old plate removing device which removes an old plate from the plate cylinder, and a plate exchange device which removes the old plate from the plate cylinder and supplies the new plate to the plate cylinder.
As shown in U.S. Pat. No. 6,393,986, a conventional plate handling apparatus comprises a plate holding device which stores an old plate removed from a plate cylinder and holds a new plate to be supplied to the plate cylinder, the first guide device which guides the old plate removed from the plate cylinder to the plate holding device, and the second guide device which positions a new plate supplied from the plate holding device and guides it to the plate cylinder. In this arrangement, when the plate holding device is swung during plate removal, the old plate removed from the plate cylinder is guided to the plate holding device through the first guide device and stored in the plate holding device. Similarly, when the plate holding device is swung during plate supply, the new plate is moved to a plate supply position where the new plate can be supplied to the plate cylinder, and is supplied to the plate cylinder through the second guide device.
In the conventional plate handling apparatus described above, the second guide device which positions the new plate before inserting it in the plate cylinder is provided separately of the plate holding device. Also, the second guide device is arranged between the plate holding device and plate cylinder. When the plate size increases, although length of the outer surface of the plate cylinder increases, the diameter of the plate cylinder does not increase compared to the length of the outer surface, and the outer shape of an inking device or the like does not become bulky. Hence, the outer shape of a printing unit itself does not become bulky so much. Meanwhile, gaps among printing units lead to a restriction on the installation space in the factory and destabilization of the tension with respect to the web. Accordingly, there is a restriction to an increase in gaps among the printing units.
Therefore, in the conventional plate handling apparatus, if the plate size increases, the plate holding device or second guide device may come into contact with other members. When the plate size increases, the entire length of the plate holding device itself increases, and the lower end (rear end) of the plate holding device comes into contact with the floor. Hence, to increase the plate size is not easy. In particular, in the case of a perfecter, in a lower plate exchange device, the space between the floor and the web to be conveyed is restricted to a certain degree. Because the plate exchange device must be stored in the restricted space, an increase in plate size cannot be coped with.